Added option to disable list caching, dynamically remove lists on low mem

app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java

@@ -19,6 +19,8 @@ package eu.faircode.email;
     Copyright 2018-2019 by Marcel Bokhorst (M66B)
 */
 
+import android.app.ActivityManager;
+import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.net.Uri;
@@ -50,6 +52,8 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private SwitchCompat swAuthentication;
     private SwitchCompat swParanoid;
     private TextView tvParanoidHint;
+    private SwitchCompat swCacheLists;
+    private TextView tvCacheListsHint;
     private SwitchCompat swWatchdog;
     private SwitchCompat swUpdates;
     private SwitchCompat swCrashReports;
@@ -60,7 +64,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private Group grpSearchLocal;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "badge", "subscriptions", "english", "authentication", "paranoid", "watchdog", "updates", "crash_reports", "debug"
+            "badge", "subscriptions", "english", "authentication", "paranoid", "cache_lists", "watchdog", "updates", "crash_reports", "debug"
     };
 
     private final static String[] RESET_QUESTIONS = new String[]{
@@ -83,6 +87,8 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swAuthentication = view.findViewById(R.id.swAuthentication);
         swParanoid = view.findViewById(R.id.swParanoid);
         tvParanoidHint = view.findViewById(R.id.tvParanoidHint);
+        swCacheLists = view.findViewById(R.id.swCacheLists);
+        tvCacheListsHint = view.findViewById(R.id.tvCacheListsHint);
         swWatchdog = view.findViewById(R.id.swWatchdog);
         swUpdates = view.findViewById(R.id.swUpdates);
         swCrashReports = view.findViewById(R.id.swCrashReports);
@@ -148,6 +154,14 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             });
         }
 
+        swCacheLists.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("cache_lists", checked).apply();
+                WorkerWatchdog.init(getContext());
+            }
+        });
+
         swWatchdog.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -238,12 +252,18 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swEnglish.setChecked(prefs.getBoolean("english", false));
         swAuthentication.setChecked(prefs.getBoolean("authentication", false));
         swParanoid.setChecked(prefs.getBoolean("paranoid", true));
+        swCacheLists.setChecked(prefs.getBoolean("cache_lists", true));
         swWatchdog.setChecked(prefs.getBoolean("watchdog", true));
         swUpdates.setChecked(prefs.getBoolean("updates", true));
         swUpdates.setVisibility(Helper.isPlayStoreInstall(getContext()) ? View.GONE : View.VISIBLE);
         swCrashReports.setChecked(prefs.getBoolean("crash_reports", false));
         swDebug.setChecked(prefs.getBoolean("debug", false));
 
+        ActivityManager am = (ActivityManager) getContext().getSystemService(Context.ACTIVITY_SERVICE);
+        int class_mb = am.getMemoryClass();
+
+        tvCacheListsHint.setText(getString(R.string.title_advanced_cache_list_hint, class_mb + " MB"));
+
         grpSearchLocal.setVisibility(Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.M ? View.GONE : View.VISIBLE);
     }
 

app/src/main/java/eu/faircode/email/ViewModelMessages.java

@@ -51,9 +51,10 @@ public class ViewModelMessages extends ViewModel {
 
     private static final int LOCAL_PAGE_SIZE = 100;
     private static final int REMOTE_PAGE_SIZE = 10;
+    private static final int LOW_MEM_MB = 64;
 
     Model getModel(
-            Context context, final LifecycleOwner owner,
+            final Context context, final LifecycleOwner owner,
             final AdapterMessage.ViewType viewType,
             long account, long folder, String thread, long id,
             String query, boolean server) {
@@ -153,8 +154,21 @@ public class ViewModelMessages extends ViewModel {
                 public void onDestroyed() {
                     Log.i("Destroy model " + viewType);
 
-                    if (viewType == AdapterMessage.ViewType.THREAD)
+                    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+                    boolean cache = prefs.getBoolean("cache_lists", true);
+
+                    Runtime rt = Runtime.getRuntime();
+                    long used = (rt.totalMemory() - rt.freeMemory());
+                    long max = rt.maxMemory();
+                    long free_mb = (max - used) / 1024L / 1024L;
+
+                    boolean lowmem = (free_mb < LOW_MEM_MB);
+
+                    if (viewType == AdapterMessage.ViewType.THREAD || !cache || lowmem) {
+                        Log.i("Remove model " + viewType +
+                                " cache=" + cache + " lowmem=" + lowmem + " free=" + free_mb + " MB");
                         remove(viewType);
+                    }
 
                     dump();
                 }

app/src/main/res/layout/fragment_options_misc.xml

@@ -127,6 +127,28 @@
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@id/swParanoid" />
 
+            <androidx.appcompat.widget.SwitchCompat
+                android:id="@+id/swCacheLists"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:text="@string/title_advanced_cache_lists"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/tvParanoidHint"
+                app:switchPadding="12dp" />
+
+            <TextView
+                android:id="@+id/tvCacheListsHint"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="48dp"
+                android:text="@string/title_advanced_cache_list_hint"
+                android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                android:textStyle="italic"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/swCacheLists" />
+
             <androidx.appcompat.widget.SwitchCompat
                 android:id="@+id/swWatchdog"
                 android:layout_width="match_parent"
@@ -134,7 +156,7 @@
                 android:layout_marginTop="12dp"
                 android:text="@string/title_advanced_watchdog"
                 app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/tvParanoidHint"
+                app:layout_constraintTop_toBottomOf="@id/tvCacheListsHint"
                 app:switchPadding="12dp" />
 
             <androidx.appcompat.widget.SwitchCompat

app/src/main/res/values/strings.xml

@@ -223,6 +223,7 @@
     <string name="title_advanced_english">Force English language</string>
     <string name="title_advanced_authentication">Show a warning when the receiving server could not authenticate the message</string>
     <string name="title_advanced_paranoid">Extra privacy features</string>
+    <string name="title_advanced_cache_lists">Cache message lists</string>
     <string name="title_advanced_watchdog">Periodically check if FairEmail is still active</string>
     <string name="title_advanced_updates">Check for updates</string>
     <string name="title_advanced_crash_reports">Send error reports</string>
@@ -250,6 +251,7 @@
     <string name="title_advanced_badge_hint">Only available on supported launchers</string>
     <string name="title_advanced_english_hint">This will restart the app</string>
     <string name="title_advanced_paranoid_hint">See the FAQ for details</string>
+    <string name="title_advanced_cache_list_hint">Memory available: %1$s</string>
     <string name="title_advanced_debug_hint">Enable extra logging and show debug information at various places</string>
 
     <string name="title_select">Select &#8230;</string>